April 17, 2018
The story goes like…
Background
- Between-group riots can increase in response to drought (Almer, Laurent-Lucchetti, and Oechslin 2017).
- Some models show scarcity can reduce conflict (Butler and Gates 2012).
Model: Scarcity reduces conflict
From Butler and Gates (2012):
\[I_i = \frac{F_i + \eta}{\sum \limits_{i = 1}^N \left( F_i + \eta \right)} \left[\sum \limits_{i = 1}^N \left( R_i - F_i \right) \right]\]
- \(I_i\): income for group \(i\).
- \(F_i\): effort dedicated to conflict/protection of resource.
- \(R_i\): resource available to group \(i\).
- \(\eta\): state-provided property protection.
Data: Social Conflict Analysis Database (SCAD)
Geocoded records of conflict (Salehyan et al. 2012).
Data: Standardized Precipitation Evapotranspiration (SPEI)
A 0.5 degree spatio-temporal grid of data from 1990-2015 (Vicente-Serrano, Beguería, and López-Moreno 2010).
Prio-Grid
Population and travel time to urban area (Tollefsen, Strand, and Buhaug 2012).
Cropland
Fraction of land as cropland and pasture (Ramankutty et al. 2008).
Property Rights
- “Rights to Resources”, 11 questions about the legal framework in each country in Africa (World Resources Institute 2014).
- Water rights for many countries globally, but missing many countries in Africa (Alden Wily et al. 2017).
Data Summary
| Variable | Mean | Std. Dev. | Min. | Max. |
|---|---|---|---|---|
| Days with riots | 0.01301 | 0.58386 | 0 | 187 |
| Riot occurred | 0.00072 | 0.0268 | 0 | 1 |
| Riot onset | 0.00069 | 0.02626 | 0 | 1 |
| Number of riots | 0.00079 | 0.03213 | 0 | 13 |
| SPEI | -0.10487 | 0.98712 | -8.01478 | 7.45265 |
| Cropland | 0.08097 | 0.14526 | 0 | 1 |
| Population | 83641.73736 | 214877.62255 | 0 | 8339141 |
Empirical Model
\[\begin{aligned} y_{it} = & \alpha + \beta \; \mbox{SPEI}_{it} + \beta_w \; (\mbox{SPEI} \times W_c) + \beta_m \; (\mbox{SPEI} \times M_c) + \\ & \gamma_{i} + \delta_{t} + \rho_{rm} + \phi_{cy} + \varepsilon_{it} \end{aligned}\]
- \(\mbox{SPEI}\): drought deviation from long-run trend.
- \(W_c\): Whether a country has laws providing for water rights.
- \(M_c\): Whether a country has laws providing for mineral rights.
Results
| Dependent variable: | ||
| Conflict Onset | ||
| (1) | (2) | |
| Drought | -0.00004 | -0.0001 |
| (0.0002) | (0.0002) | |
| Drought Mean Response | 0.851*** | 0.856*** |
| (0.023) | (0.023) | |
| Drought X Priv Water | 0.0001 | |
| (0.0005) | ||
| Drought X Priv Minerals | 0.0005 | |
| (0.001) | ||
| Constant | 0.001 | 0.001 |
| (0.002) | (0.002) | |
| Observations | 43,278 | 42,006 |
| R2 | 0.042 | 0.042 |
| Adjusted R2 | 0.040 | 0.040 |
| Residual Std. Error | 0.033 (df = 43178) | 0.033 (df = 41906) |
| F Statistic | 19.036*** (df = 99; 43178) | 18.665*** (df = 99; 41906) |
| Note: | p<0.1; p<0.05; p<0.01 | |
| ‘Priv’ is whether the law provides for private resource rights. ‘Trad’ | ||
| is whether the law provides for traditional or cultural resource rights. | ||
References
Alden Wily, Liz, Fabrice Dubertret, Peter Veit, Katie Reytar, and Nicholas Tagliarino. 2017. “Water Rights on Community Lands: Landmark’s Findings from 100 Countries.” Land 6 (4). MDPI AG:77. https://doi.org/10.3390/land6040077.
Almer, Christian, Jérémy Laurent-Lucchetti, and Manuel Oechslin. 2017. “Water Scarcity and Rioting: Disaggregated Evidence from Sub-Saharan Africa.” Journal of Environmental Economics and Management 86. Elsevier BV:193–209. https://doi.org/10.1016/j.jeem.2017.06.002.
Butler, Christopher K, and Scott Gates. 2012. “African Range Wars: Climate, Conflict, and Property Rights.” Journal of Peace Research 49 (1). SAGE Publications:23–34. https://doi.org/10.1177/0022343311426166.
Ramankutty, Navin, Amato T. Evan, Chad Monfreda, and Jonathan A. Foley. 2008. “Farming the Planet: 1. Geographic Distribution of Global Agricultural Lands in the Year 2000.” Global Biogeochemical Cycles 22 (1). American Geophysical Union (AGU):n/a–n/a. https://doi.org/10.1029/2007gb002952.
Salehyan, Idean, Cullen S. Hendrix, Jesse Hamner, Christina Case, Christopher Linebarger, Emily Stull, and Jennifer Williams. 2012. “Social Conflict in Africa: A New Database.” International Interactions 38 (4). Informa UK Limited:503–11. https://doi.org/10.1080/03050629.2012.697426.
Tollefsen, Andreas Forø, Håvard Strand, and Halvard Buhaug. 2012. “Prio-Grid: A Unified Spatial Data Structure.” Journal of Peace Research 49 (2). SAGE Publications:363–74. https://doi.org/10.1177/0022343311431287.
Vicente-Serrano, Sergio M., Santiago Beguería, and Juan I. López-Moreno. 2010. “A Multiscalar Drought Index Sensitive to Global Warming: The Standardized Precipitation Evapotranspiration Index.” Journal of Climate 23 (7). American Meteorological Society:1696–1718. https://doi.org/10.1175/2009jcli2909.1.
World Resources Institute. 2014. “Rights to Resources: The Status of Local Natural Resource Rights in National Laws in Sub-Saharan Africa.” Washington, DC: World Resources Institute. https://datasets.wri.org/dataset/rights-to-resources-map.